Brake pipe vent control



May 6, 1952 5, KELLER 2,595,466

BRAKE PIPE VENT CONTROL Filed Feb. 11, 1949 INVENTQR Siegfried Keller ATORNE'JS Patented May 6, 1952 2,595,466 BRAKE PIPE VENT CONTROL SiegfriedKeller, Effretikon, Switzerland, assignor to Machine Tool WorksOerlikon, Administration Company, Zurich-Oerlikcn, Switzerland, a

company of Switzerland Application February 11, 1949, Serial No. 75,824

In Switzerland February 16, 1948 5 Claims. 1

In accordance with the international regula tions governing brakes ongoods trains, the control valve of each wagon braked should, when theindirect-acting pneumatic brakes are applied, automatically produce aspecific decrease in pressure in the continuous brake-line with a viewto achieving a quick response of the brakes throughout the train.

In the existing types of control valves this is generally achieved by anarrangement whereby a so-called accelerator responds to the decrease inpressure in the continuous brake-line initiated from the drivers cabin,said accelerator opening a valve by means of which compressed air in thebrake-line can suddenly expand into a specific additional volume. Thisproduces a specific rapid drop in pressure in the brake-line, which dropis propagated in like manner through all the control valves to the endof the train. Such accelerators may come into action only when thebrakes are first applied and must remain inoperative during thecontinued application or release of the brakes. As the above-mentionedadditional volume is in most cases comprised within the control valvecasting, it involves an increase in the dimensions and weight of thisappliance.

The invention relates to a device for indirectacting pneumatic brakesfor achieving a sudden tapping of the pressure medium in the continuousbrake-line at the moment when the brakes are first applied, said devicecomprising a rocker which is controlled by a piston actuated by the dropin pressure in the brake-line and momentarily opens a valve leading fromthe brake-line to the atmosphere, being thereupon tipped up by themovement of said piston to such an extent that the operated valve canreturn to'its position of closure, said rocker being, after the brakeshave been initially applied, held in its tipped-up position,independently of the further movements of the piston operating it, by alooking member controlled by the brake cylinder pressure, until suchtime as the pressure in the brake cylinder has dropped to apre-determined minimum value upon the release of the brake.

In the enclosed drawing the object of the invention is diagrammaticallyrepresented; in said drawing:

I designates a known type of control valve for indirect-acting pneumaticbrakes, II the compressed air reservoir, III the brake cylinder, IV therocker accelerator, V the locking member.

The piston 55 of a known type of indirectacting control valve Iconnected to the continw ous brake-line I slides in a housing it withwhich; 1

the brake-line I is connected, in response to a decrease in pressure inthe brake-line I effected from the drivers cabin with a view to app ythe brakes, to the left as a result of the throttling effect of the duct2. The guide bush 4, in which the rocker 5 (comprising two arms l1, l8forming a right angle) is pivotally mounted at 6, is thereby likewisedisplaced out of a rest position to the left in opposition to the slightpressure exerted by the spring 7.

The arm ll of the rocker 5 which, in the rest position shown in thedrawing is in alignment with the tappet 8 of the accelerator valve 9,engages this tap'pet and opens the valve against the influence of aspring H5 pressing the valve on its seat. Thus the brake line I isconnected with the atmosphere through the housing l5. Owing to thesudden escape of compressed air the piston 3 is impelled still furtherto the left to a working position. Shortly before reaching this positionthe arm 58 of the rocker 5 bears against the edge H} of the housing I5,whereupon it is pivoted about the pin 6. At this moment the tappet 8 ofthe valve 9 is released and the latter is closed again by the spring It.

To prevent the accelerator from coming into action again in the courseof the continued application or the release of the brakes, the guidesleeve i is arrested by the plunger II in the groove [2 as soon as aspecific brake cylinder pressure on the piston Hi corresponding to thefirst pressure stage is produced via the conduit I3. Only when, uponrelease of the brakes-- which is performed by increasing the pressure inthe brake pipe l-the brake cylinder pressure has dropped below that ofthe first pressure stage, can the brake-line pressure acting on theplunger ll overcome the brake cylinder pressure exerted on the piston14, whereupon the guide-sleeve t is released and slides back to itsinitial position under the pressure exerted by the spring I, to operateagain, in the manner described, when the brakes are again applied.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is:

1. In a pneumatic brake, in combination with a brake line, a brakecylinder and a compressed air reservoir, an accelerator valve having avalve seat, a movable valve body and a spring pressing said valve bodyagainst said valve seat; a control valve comprising a movablepressure-actuated piston, a cylinder containing said piston andu-havins, o da o ne ed w h-sai brake n and the other side connectedwithvsaidcompressed air reservoir, whereby said piston is actuated bydifference in pressure between said brake line and said compressed airreservoir, a casing communicating with said cylinder, a rocker, a bushmovable along with said piston and pivotally supporting said rocker,said rocker being movable along with said piston in the direction ofmovement of said valve body to open said accelerator valve against thepressure of said spring when said piston is moved, said casingconnecting said brake line with said accelerator valve, said casinghaving a stop engaging a part of said rocker during movement of saidpiston and moving said rocker away from said valve body, whereupon thevalve body is closed by said spring, a movable locking member lockingsaid bush to hold said rocker in its position away from said valve body,

and means connected with said locking member and said brake cylinderandactuating said looking member by pressure in the brake cylinder to locksaid rocker.

2. In a pneumaticbrake having a brake line, in combination, a casingconnected with the brake line, a pistonmovable Within said casing andhaving one side subjected to pressure in said brake line, a compressedair reservoir connected with said casing and supplying compressed air tothe other side of said piston to normally balance said piston, wherebysaid piston is moved when pressure drops in said brake line,,a valve insaid casing for connecting said one side of the piston with theatmosphere and having a valve seat, a valve body and resilient meanspressing said valve body against said valve seat to maintain said valvenormally closed, a member movable along with the piston from a restposition to a working position, said member engaging said valve bodyduring this movement and opening the valve against the action of saidresilient means to vent air from said brake line, said casing comprisinga member engaging the first-mentioned member during the movement of thepiston and causing the first-mentioned member to disengage from saidvalve body, whereupon said valve is closed by said resilient means andthe venting of air from said brake line is interrupted.

3. In a pneumatic brake having a brake line. in combination, a casingconnected with the brake line, a piston movable within said casing andhaving one side subjected to pressure in said brake line, a compressedair reservoir connected with said casing and supplying compressed air tothe other side of said piston to normally balance said piston, wherebysaid .piston is moved when pressure drops in said brake line, a valve insaid casing for connecting said one side of the piston with theatmosphere and having a valve seat, a valve body and resilient meanspressing said valve body against said valve seat to maintain said valvenormally closed, a member movable along with said piston from a restposition to a working position, said member engaging said valve bodyduring this movement and opening the valve against the action of saidresilient means to vent air from .said brake line, said casingcomprising a member which is out of engagement with the first-mentionedmember in the rest position of the latter and which engages thefirst-mentioned member during the movement of the piston to disengagethe firstmentioned member from said valve body, whereupon said valve isclosed by said .resilient means and the venting of air.fromsaidbrakelineis interrupted.

4. In a pneumatic brake having a brake line, in combination, a casingconnected with the brake line, a piston movable within said casing andhaving one side subjected to pressure in said brake line, a compressedair reservoir connected with said casing and supplying compressed air tothe other side of said piston to normally balance said piston, wherebysaid piston is moved when pressure drops in ,said brake line, a valve insaid casing for connecting said one side of the piston with theatmosphere and having a valve seat, a. valve body and resilient meanspressing said valve body against said valve seat to maintain said valvenormally closed, a guide bush located in said casing and movable by saidpiston from a rest position to a working position, a rocker mounted uponsaid guide bush and movable along with said guide bush as well astransverse- 1y thereto, said rocker engaging said valve body during themovement to a working position and opening the valve against the actionof said resilient means to vent air from said brake line, said casingcomprising, a stop engaging said rocker during the movement of thepiston and causing the rocker close to the end of this movement to movetransversely to the guide bush and thereby become disengaged from saidvalve body, whereupon said valve is closed by said resilient means andthe venting of air from said brake line is interrupted.

5. In a pneumatic brake having a brake line and a brake cylinder, incombination, a casing connected with the brake line, a piston movablewithin said casing and having one side subjected to pressure in saidbrake line, a compressed air reservoir connected with said casing andsupplying compressed air to the other side of said piston to normallybalance said piston, whereby said piston is moved when pressure drops insaid brake line, a valve in said casing for connecting said one side ofthe piston with the atmosphere and having a valve seat, a valve body andresilient means pressing said valve body against said valve seat tomaintain said valve normally closed, a member movable along with thepiston from a rest position to a working position, said member havingmeans engaging said valve body during this movement and opening thevalve against the action of said resilient means to vent air from saidbrake line, said casing comprising a member engaging said means duringthe movement of the piston and causing the means to disengage from saidvalve body, a locking device for locking said first-mentioned member insaid working position, and pneumatic means connected with said lockingdevice and said brake cylinder and actuating said locking deviceWhen-said brake cylinder is charged.

SIEGFRIED KELLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

